<!DOCTYPE html>
<html>

	<head>
		<meta charset="UTF-8">
		<title></title>
	</head>
<style type="text/css">
	#main{
		margin-top: 300px;
		width: 100px;
		height: 200px;
		background-color: #0000C0;
		color: red;
	}
</style>
	<body>
		<div id="main">
			很开心
		</div>
	</body>

</html>